2002 Montero SportDecember 21, 2014December 21, 2014When in park, my Montero idles smooth but when I put it in gear, it “misses” or idles rough. What can cause this to happen? Keywords:idle problemmontero 1 thought on “2002 Montero Sport” Freeautomechanic December 22, 2014 at 9:42 pm If it also runs smooth off idle and has no check engine light on, I would attribute the issue to a dirty throttle body. This is quite common for a vehicle of its age. Remove the hose connected to the throttle body. Use a cotton rag or shop towel and spray some brake cleaner on the rag (DO NOT spray in the throttle body) Hold the throttle wide open and use the heavily saturated rag to wipe the throat and the butterfly specifically the thin outer portion of the butterfly and where it would come to close contact with the throat of the throttle body. What happens is dirt, carbon, debree, etc build up in this area and will restrict the airflow just enough to cause this issue. In park the Idle speed control is able to take care of this, but not once put in gear. Of course if the check engine light is on, pull the codes first and post them back here. If it runs rough when you are driving it, tune up may be needed. Let me know if you need further assistance by posting below in the comments. And why not, its free. Comments are closed.